/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.skatiger.jrove.renderer;

import java.io.IOException;

import org.skatiger.jrove.ViewContext;
import org.skatiger.jrove.component.UIComponent;

/**
 * base renderer. render component as html
 * 
 */
public abstract class Renderer {

    public boolean isRendersChildren() {
        return false;
    }

    /**
     * @throws IOException
     *             if an input/output error occurs while rendering
     */
    public void encodeBegin(ViewContext context, UIComponent component)
            throws IOException {
        if (context == null)
            throw new NullPointerException("context");
        if (component == null)
            throw new NullPointerException("component");
    }

    /**
     * Render all children if there are any.
     * 
     * Note: this will only be called if getRendersChildren() returns true. A
     * component which has a renderer with getRendersChildren() set to true will
     * typically contain the rendering logic for its children in this method.
     * 
     * @param context
     * @param component
     * @throws IOException
     */
    public void encodeChildren(ViewContext context, UIComponent component)
            throws IOException {
        if (context == null)
            throw new NullPointerException("context");
        if (component == null)
            throw new NullPointerException("component");

        if (component.getChildCount() > 0) {
            for (UIComponent child : component.getChildren()) {
                if (!child.isRendered()) {
                    continue;
                }

                child.encodeAll(context);
            }
        }
    }

    /**
     * @throws IOException
     *             if an input/output error occurs while rendering
     */
    public void encodeEnd(ViewContext context, UIComponent component)
            throws IOException {
        if (context == null)
            throw new NullPointerException("context");
        if (component == null)
            throw new NullPointerException("component");
    }

    public String convertClientId(ViewContext context, String clientId) {
        if (context == null)
            throw new NullPointerException("context");
        if (clientId == null)
            throw new NullPointerException("clientId");
        return clientId;
    }
}
